Coolant temps

[snaponbob]

Last year I had no issues with coolant temps in my 04M3 at solo events. This year, due to Covid issues, I did a couple small (5-6 cars) track sessions at RPM in Iowa. At the second event, in the afternoon the ambient temps were low 90s, and my temp gauge spiked into the red area. I backed off and the temps came down. I trailered the car and came home. There are zero symptoms of a cracked head or failed head gasket. No fluid losses, no leaks. Replaced the radiator with a CFM all aluminum unit, new thermostat and fan clutch. The pump was clean and spun smoothly. At many recommendations, I went with distilled water and water wetter. I just came back from a Solo event at Lincoln, Ne. Temps were low 90s and in a 60 second run, the temps climbed to about 3/4 up on the gauge. Aux fan is functioning properly. An infrared "heat gun" was showing temps in and out of the radiator under 200°, and at the t-stat housing I read under 200.

Is the only temp sensor in the lower radiator hose? M54s have that one (outlet temp sensor) and another near #5 in the head). Are there two sensors in the S54?

[lmtfi]

Are you opening the hood after you come off between sessions? I have run with an OE radiator in 99-101F temps with no indication past exact mid-range.

[snaponbob]

I do. The temps are up as I leave the finish line.

[snaponbob]

BTW, rarely climbed last year. It started at private track session at RPM in Iowa. First track sessions a few weekends ago were fine. Second visit the outside temps were in the mid 90s in the afternoon and the temp spiked into lower part of the red, but came down as soon as I slowed. NO symptoms of a head gasket issue. This weekend I was at Lincoln airport for a T&T and a Solo event. Pretty toasty there . Same stuff. But, o had installed a CSP aluminum radiator, new fan clutch, and t-stat, plus distilled water and water wetter. Infra red readings did not match the temp gauge.

Electric pusher fan is working properly. Plan on taking a scan tool to read data streams at the next event.

[dworthy]

If the lower and upper hoses are both at 200 degrees, that would point to a clogged radiator, for the water is just shooting thru it without a chance to cool. Radiator shops can to a flow test to see how much water is actually going thru a radiator, would be worth giving a try.

I am also guessing that you are not using a mechanical puller fan?

[snaponbob]

At the risk of sounding like an a$$hole, did you read my initial post?

" Replaced the radiator with a CFM all aluminum unit, new thermostat and fan clutch."

In the US market, E46 M3s come with an electric pusher, and a belt driven clutched puller fan. As for the OEM radiator that I removed, it did not feel "heavy" like a clogged one would. I have replaced a LOT of E36 radiators and sort of have a sense of how they feel. Since the symptoms have seemingly not changed, I did some more digging. I did locate the actual temp sensor, but I was confused by the description of the part. Is described as an oil/coolant sensor. Once I found where it is located, I ordered a new one and will install it tomorrow.

The M54 has an "outlet temp sensor" in the same place in the lower radiator hoes, but is described differently. The actual engine temp sensor on the M54 is in the head, and since the S54 locates it in a hard pipe further up front on the engine, I was confused. I'll have a better handle on this tomorrow. The infrared readings of different points of the engine and radiator lead me to believe that this sensor may be the problem, as the readings do not match to gauge in the cluster. I sure hope that's the problem !!

[dworthy]

Yes I did, and no I am not taking offence. Not every new part works as intended, you could have one that is bad like the ports got blocked while welding on the side caps thus the recommendation for a flow test.

Yes the M-54's have an outlet temp sensor, which is nice for when you are looking for cooling issues so you can see if the radiator is working properly. This goes hand in hand with the electrical thermostat. The S-54 as you know still uses a mechanical thermostat, so it will pull the temp from the sender between #1 and #2. This is a common part to fail, and you will get a code for temps not matching.

[snaponbob]

Yes I did, and no I am not taking offence. Not every new part works as intended, you could have one that is bad like the ports got blocked while welding on the side caps thus the recommendation for a flow test.

Yes the M-54's have an outlet temp sensor, which is nice for when you are looking for cooling issues so you can see if the radiator is working properly. This goes hand in hand with the electrical thermostat. The S-54 as you know still uses a mechanical thermostat, so it will pull the temp from the sender between #1 and #2. This is a common part to fail, and you will get a code for temps not matching.

No codes. Finally found the temp sensor between #1 & #2, but as you already know, it's in the pipe going into the back of the t-stat housing. When I was working on a 525 some years ago, I had INPA and DIS available. Sadly, that laptop died. I then had a forum member (driiven) configure a replacement laptop with those programs but I never was able to get it to work, and he never replied to my calls for help. When working on the 525 I was able to see the radiator outlet and engine temps. Using my Snap-On Solus Ultra I see only engine temps, but not outlet temps.

So, at this point, t-stat is new, CFS all aluminum radiators new, fan clutch is new. Pump is functional. When the cooling system and block were drained, the fluid showed no particulates and was clean. Using an infra red heat sensor, temps at the t-stat housing and both hoses seem to indicate the engine is not nearly as hot as the gauge shows. Currently I have to intake box pulled away from the throttle bodies and will be replacing the sensor today. I can not duplicate race conditions away from competition so will have to wait for next weekend to see happens.

If this were an M or (US) S 50 or 52, I would expect a cracked head, but there was never an overheat in the year of autocross events (hundreds of runs by two drivers) to cause a head to crack (as 50s and 52s are prone to do). Also, no idle or running issues to indicate a blown head gasket. So, all my money is on the temp sensor in the return tube. Otherwise, I may have to pull the head, but not until comp and leak down tests. I did those when I bought the car with excellent results, so I will have a baseline.

[snaponbob]

More fun stuff. Seems that the two temp sensors co-mingle data !! Depending on which I disconnect and in what sequence, information displayed in the data stream on my Snap-On Solus Ultra was --- curious. If I disconnected the temp sensor in the coolant return pipe FIRST, the reading would drop some 5-15 degrees below ambient temps, if at all. If I disconnected the lower (fan) sensor first, the voltage reading on the data stream would go from +3.5 VDC to 5.0 VDC, and coolant temp would not change. If I ten unplugged the return pipe sensor it would sometimes drop to 50(ish) degrees, or sometimes drop to -52 degree F. Before I disconnected ANYTHING, ambient temps in my shop and everywhere in the engine compartment was 78F and the sensor was showing 82F.

Waiting for the new sensor today and will do the readings again.

[dworthy]

As I am sure you know since the E-36's the temp gauge has been "buffered" While the M3 has a smaller buffer than the stock cars, it is still there. IIRC, it gets to the half-way mark at 130 degrees and stays there until 190/200 degree F. There is a way to reduce that buffer of course, but you will need to have access to a programmer like NCS for Dummies.

What does the hidden features on the dash say for temps?

[snaponbob]

I forget how to get to that feature.

Another thing -- I received a new water pump with a metal impeller. The impeller clearly is a casting, and the blades are not machined at all. I can't imagine that is a good thing. The pump that is currently in the engine may be OE, but I have no way to know. It's impeller is black "plastic", has sharp edged curved blades, is completely intact, and is tight and smooth when spun. Thoughts?

[dworthy]

The OEM water pump has plastic impellers IIRC for I replaced my about 5 years ago and cannot remember exactly. There are aftermarket ones out there with a metal impeller, so perhaps you have one of those? The plastic works pretty good IMO if you replace the pump on a regular basis.

Video for the hidden menu: https://www.youtube.com/watch?v=wjKt0ZQBV2U

If the water pump spin smoothly, and the impellers look good, I would think it is just fine.

[slides]

Recently did MVP at Road America. They compiled the last 3 hours into a 1 hr session for everyone and after about 45 min of going hard the needle was started to go past center. Car has a new thermostat and water pump. Ambient air was a cool 74F.

[snaponbob]

Ran the car hard in an SCCA Pro Solo this weekend. Saturday afternoon, the temps were low/mid 80s. After 4 back to back runs, I went through the menu on the cluster and found the temps was about 96/97C and that is 207F but the needle was 3/4 of the way up. On 36s that would usually result in 215/220F. If the needle is in the middle, the menu reading is 89/90c. So, maybe the cluster's fuel gauge has become a little wonky.

[dworthy]

It comes down to coding, as the stock "buffer" should be 160F to 230F for the center mark on the gauge on the stock cluster. Now you can go in there and change it if you have the right tools: https://www.e46fanatics.com/threads/diy-changing-temperature-gauge-buffer-range-with-pa-soft-1-4.1013600/

This is something I still need to do on the wagon, and maybe on the M3 as well, for the M3 has a smaller buffer.

[snaponbob]

It's weird that last year (although without track time) never saw the needle GET to 3/4 high, yet here we are this year. REALLY odd was that I was not seeing coordinated readings (cluster menu 7.0, infra red readings, and scanner data stream as well as oil temps) until BOTH temp sensors were replaced. But, a win is a win is a win !!

Side note -- I was starting to see cooling issues with my 06 Chevy Express 3500 6 liter tow vehicle. Hoses, radiator, fan clutch (BIG difference), water pump assembly, and coolant flush, and THAT is sorted as well.

Now, if I can improve ME around those cones, it will be a wonderful triad!!!.

[dworthy]

Practice, practice, and more practice. You could even pay for an Instructor to ride along a give a couple of pointers too.

[snaponbob]

Practice, practice, and more practice. You could even pay for an Instructor to ride along a give a couple of pointers too.

Well, for what it's worth, I took the 46 M3 up to RPM in Iowa. My co-driver from last was surprised at the times I was turning for my first track time since 1985 at Summit Point in a Solo D/SP built 77 Civic. He has a LOT of NASA and SCCA track event time, and done many enduros at RPM (formerly MAM). He jumped in my time and predictably was on my same times in a hurry. He admitted he could get another second or so out of the car, and I agreed but said I could as well. HE agreed. Since my cooling system issues are behind me know, I will doing more track stuff.

That said, "practice practice practice" in Solo does NOT make one better. Breaking bad habits and enhancing good habits is what it is about. I have paid for schools, and taught as well (at a local level). I am still getting used to the massive differences between my 46 and my past two 36s. Now that an brake issue that [plagued me last week was resolved in March (bad master cylinder), and wider wheels and rubber, plus a better setup/alignment/shock settings, the car came alive this last weekend. The car is SO calm yet REALLY fast, breaking habits will be easier as I am not chasing it.

Can't wait for the next event.


That said

[dworthy]

Yes, the S-54 loves to scream, and it can take the abuse has a very nice power band from about 3.5k to 6.5k. I haven't had time nor the opportunity to get back out as I am moving more towards detailing, and wrenching. Of course I have the autobahn here and at times take the car up to 270 kph if the road is clear, which is harder to do nowadays. It is fun to let the car stretch it legs, and I have made her more of a garage queen than anything else for I only do about 5k a year on the car.

[snaponbob]

Yes, the S-54 loves to scream, and it can take the abuse has a very nice power band from about 3.5k to 6.5k. I haven't had time nor the opportunity to get back out as I am moving more towards detailing, and wrenching. Of course I have the autobahn here and at times take the car up to 270 kph if the road is clear, which is harder to do nowadays. It is fun to let the car stretch it legs, and I have made her more of a garage queen than anything else for I only do about 5k a year on the car.

Here is the US, some states have loose or no emissions testing. Where I live, there is no exhaust testing. My M3 is almost completely set up as a road capable competition car. Seats are Corbeat FX1 Pro, belts are 4 point 3" and the OEM belts are still in place, and the steering wheel is 12" without an airbag. Needless to say, the suspension has been upgraded, rear subframe supports are welded in place, and more. Because the SCCA autocross rules for my class require cats I am restricted to what I can do to the exhaust manifolds. So, the rules allow aftermarket cats but must have 100 cells. A friend had a beautiful tube manifold built with a single 100 cell cat, but since the rules require the cat to be no further than 6" away from stock location, his setup cost somewhere around $4500 to build. I did something different. I know a vendor who sells 4" diameter cats, and since the stock cats are -- TA DA -- 4" in diameter, SWAP !!! And boy was THAT a challenge !!! A 2 into 1 collector into a single 3.5" exhaust finished the exhaust. Intake has limits to changes so I opted for an Eventuri air intake but H had to maintain the OEM airbox. With a tune, this things is FAR stronger than stock. Others who have dyno'ed similar setups are putting 325-330hp to the ground. It pulls hard to about 7500, but falls off modestly to the 8000 rpm fuel cutoff. The 36 would go blap blap blap blap endlessly at 7000 cut off, but the S54 feels like it is seizing up (!!!!) when it hits redline ---- it's almost neck snapping and always sort of scary !! There is enough power to create forward bite (traction) issues on 285/30-x 18 RE71 on 18x10.5" wheels. He is strong.

[S14]

It's weird that last year (although without track time) never saw the needle GET to 3/4 high, yet here we are this year. REALLY odd was that I was not seeing coordinated readings (cluster menu 7.0, infra red readings, and scanner data stream as well as oil temps) until BOTH temp sensors were replaced. But, a win is a win is a win !!

Side note -- I was starting to see cooling issues with my 06 Chevy Express 3500 6 liter tow vehicle. Hoses, radiator, fan clutch (BIG difference), water pump assembly, and coolant flush, and THAT is sorted as well.

Now, if I can improve ME around those cones, it will be a wonderful triad!!!.

I'm having weird cooling issues too. My cluster will go to 3/4 hot and the OBD scanner will show 185F. At 190f the cluster is at the edge of the red block.

In the morning when everything is cool, I did the test and outside temp was 25c, scanner says the coolant temp is 25c. cluster test shows 34c. wat.

I'll replace both sensors and re-rebleed the system, thanks for sharing your problem and repair, I hope my issue is similar!

[slides]

How much of an impact can the side fan/radiator shroud have on cooling?

The car doesn't have the side pieces and I wonder if that would contribute to inability of evacuating the hot air.